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Permethrin Around Dogs and Cats: What the Labels Say

By Andrew Rothaus, Founder · · Updated

Short answer: Some permethrin products are labeled for dogs; the label sets the limits. NPIC says cats are more sensitive to permethrin than dogs or people because their bodies take a long time to break it down. One dog label, EPA Reg. No. 11556-142, reads DO NOT USE ON CATS, MAY BE FATAL. NPIC says your veterinarian can help you choose.

Which permethrin products are labeled for dogs?

NPIC names spot-on treatments for dogs among the places permethrin turns up. Its general fact sheet, reviewed in July 2009, says permethrin is used in cattle ear tags and flea collars, or in spot-on treatments for dogs, and counts more than 1400 registered products containing permethrin. Its technical fact sheet adds that some permethrin products are labeled for use only on dogs.

Past that, the label on the package is the whole answer. The EPA stamped label for K9 Advantix II Medium Dog, EPA Reg. No. 11556-142, lists permethrin among its active ingredients. It is for monthly use only on dogs and puppies 7 weeks of age and older and weighing 11 to 20 lbs, and says: "For external use on dogs only. Do not use on animals other than dogs." Those numbers belong to that one product.

Permethrin turns up well beyond dog products: NPIC says products containing it may be used on livestock and pets, in structures and buildings, and on clothing. We take up whether mosquito repellent can go on a dog separately. EPA's advice is to always read the label first, and to keep all products out of the reach of pets and children.

Why is permethrin toxic to cats in particular?

Because it takes a cat's body a long time to break permethrin down, NPIC says, cats are more sensitive to it than dogs or people. On the reason, NPIC's technical fact sheet says cats can be sensitive to products with high concentrations of permethrin, "possibly due to insufficient glucoronide conjugation capability." A 2007 paper in the Journal of Feline Medicine and Surgery says a feline deficiency of glucuronidase transferase "may lead to prolonged detoxification." Both sources hedge, and the hedge is theirs.

The signs can come late. NPIC's technical fact sheet says cats exposed dermally to some permethrin products may experience hyperexcitability, depression, ataxia, vomiting, anorexia, tremors or convulsions, and that symptoms can begin within a few minutes or up to three days after the exposure. The 2007 paper says signs usually present within 3 hours of exposure but can be delayed until 72 hours.

The 2007 paper calls permethrin-based spot-on preparations contraindicated in cats because of the high risk of toxicosis. It reviewed 286 cases of inappropriate feline exposure to those preparations reported to the Veterinary Poisons Information Service (VPIS), London: 96.9 percent were symptomatic, and death occurred in 10.5 percent of cases.

What do dog spot-on labels say about cats?

They say it in capitals. The label for K9 Advantix II Medium Dog, EPA Reg. No. 11556-142, which lists permethrin among its active ingredients, prints DO NOT USE ON CATS, MAY BE FATAL, then: "Keep cats away from treated dogs for 24 hours. If applied to a cat or ingested by a cat, contact your veterinarian immediately." That wording, and that 24 hours, belong to that label.

EPA has looked at how well such warnings work. EPA's evaluation of pet spot-on products found that label warnings against use of dog products on other animals, especially cats, "are not working well enough."

The rule fits on one line. NPIC: "Dog products should never be used on cats." FDA: "If the product is for use on dogs, don't use it on cats." EPA says never to apply dog products to cats. The American Veterinary Medical Association says to be especially careful using insect control products for or around cats, and never to use a product that is not approved for cats "because the results could be deadly."

What happens if a dog licks permethrin?

Drooling and lip-smacking are the signs NPIC describes. Its general fact sheet says animals that have licked treated skin may drool a lot or smack their lips. Its technical fact sheet says this is believed to be a result of licking at the application site, thought to be caused either by the taste or a tingling sensation in the mouth.

The K9 Advantix II Medium Dog label tells owners not to let it happen: "Do not get this product in your dog's eyes or allow your dog to ingest this product." It lists skin irritation such as redness and scratching among possible side effects, says vomiting or diarrhea have also been reported, and says to consult your veterinarian if these occur.

NPIC says dermal exposures to cats and dogs may cause temporary paresthesia and neurological signs. Its general fact sheet also reports a feeding study: dogs fed permethrin for up to 2 years had more tremors than dogs that did not eat it. Each licking description above is about product applied to an animal's skin.

What about a cat that lives with a treated dog?

A cat does not have to be treated to be exposed. The 2007 Journal of Feline Medicine and Surgery paper says cats are also at risk from secondary exposure through contact with other pets treated with a permethrin spot-on. EPA's 2006 reregistration decision says there have been severe adverse reactions, including deaths, in cats exposed directly to concentrated permethrin products or secondarily exposed to treated dogs.

NPIC's technical fact sheet describes one case: a cat was in proximity of two large dogs treated with a permethrin product 48 hours after treatment, and between 18 and 24 hours after being near the dogs it developed signs including agitation, tremors, seizures and ataxia. International Cat Care says permethrin can transfer to a cat's coat when the cat rubs against a recently treated dog, or even sits on the same furniture.

The household rules we found are about product on an animal. FDA says that if you use spray or spot-on products on multiple pets, apply to one pet at a time and keep the treated animal separated from the others until the product dries, to prevent one animal from grooming another. It calls that especially important if the product is only for use in dogs and you have a cat. NPIC says many products require treated animals to be separated after treatment to prevent touching and licking.

What does a permethrin clothing label say about pets?

Very little. The EPA stamped label we read, Traveler's Supply Inc. Permethrin Clothing and Gear Insect Repellent, EPA Reg. No. 81402-1, prints DO NOT APPLY TO SKIN and says: "Do not apply this product in a way that will contact children, either directly or through drift. Except when applying to clothing, do not allow adults or pets to enter until sprays have dried." Clothing application is the stated exception, so the label gives no rule about pets and treated clothes.

Its clothing directions are addressed to the wearer: never apply it to clothing while it is being worn, and hang treated clothing to dry for at least 2 hours, 4 hours under humid conditions, before wearing. Its storage line names pets: "Store in a cool dry area away from children and pets." We found no mention of cats or dogs on it.

On clothing treatments, NPIC says they "are only intended for use on fabrics," and CDC says: "Do not use permethrin products directly on skin." More in treating clothing with permethrin and pairing it with a skin-applied repellent.

On cats, we found one statement. International Cat Care says permethrin is also sometimes infused in clothing to repel ticks, mosquitoes and flies, and that "there's no evidence to show that cats have been poisoned through exposure to these items of clothing." It recommends contacting the manufacturer if there is any concern. We leave that as an absence of evidence. We found no source that states a drying rule or a waiting time for permethrin-treated clothing with respect to pets.

Who do you call after an exposure?

Your veterinarian, NPIC, or an animal poison-control line. EPA's flea and tick guidance says that if your pet experiences an adverse reaction, immediately bathe the pet with mild soap and rinse with large amounts of water, and contact your veterinarian, the National Pesticide Information Center at 1-800-858-7378, or both, right away. FDA says to call your veterinarian if your pet shows symptoms of illness after using a product, and to look for dizziness, wobbliness, incoordination, poor appetite, depression, vomiting, diarrhea or excessive salivation.

NPIC says that for emergencies you should contact your veterinarian or the ASPCA Animal Poison Control Center at 1-888-426-4435. The ASPCA's own page gives the same number, 24 hours a day, 365 days a year, and says a consultation fee may apply. Pet Poison Helpline says it is available 24/7 at (855) 764-7661 and lists a one-time consultation fee of $89 per incident.

For a cat, International Cat Care says that if you are worried you may have applied a flea product containing permethrin to your cat, or if your cat has been in contact with a dog treated with permethrin, contact your veterinary team immediately.

Common questions

Is permethrin toxic after it dries?

No source we read gives a drying rule for permethrin-treated fabric with respect to pets, so we do not give one. The until-dry rules we found are about product applied to an animal: FDA says to keep a treated animal separated from other pets until the product dries, and the K9 Advantix II Medium Dog label says not to have contact with the treated area until completely dry. The clothing label we read, EPA Reg. No. 81402-1, says "Except when applying to clothing, do not allow adults or pets to enter until sprays have dried," which leaves clothing application out of that rule.

Can I use permethrin on my dog for fleas?

Some products carry EPA labels for exactly that, and the label and your veterinarian decide which. FDA says to read the label before use even if you have used the product many times before, because the directions or warnings may have changed, and NPIC says your veterinarian can help you compare and select the most appropriate products.

How long does one dog label say to keep a cat away from a treated dog?

One label we read gives a number, and the number is that label's alone. The K9 Advantix II Medium Dog label, EPA Reg. No. 11556-142, which lists permethrin among its active ingredients, says "Keep cats away from treated dogs for 24 hours," and "If applied to a cat or ingested by a cat, contact your veterinarian immediately."

Can I treat clothes with permethrin if I have a cat?

The label we read, EPA Reg. No. 81402-1, carries no cat instruction at all, so we do not turn its drying times into a rule for cats. What it does address is the person doing the treating: make all applications outdoors, never apply it to clothing while it is being worn, hang treated clothing to dry for at least 2 hours (4 hours under humid conditions) before wearing, and store the product away from children and pets. NPIC says to hang treated fabrics outdoors and allow them to dry completely before wearing them.

Sources

  1. NPIC, Permethrin General Fact Sheet. https://npic.orst.edu/factsheets/PermGen.html
  2. NPIC, Permethrin Treated Clothing. https://npic.orst.edu/pest/mosquito/ptc.html
  3. CDC, About Permethrin-Treated Clothing and Gear. https://www.cdc.gov/mosquitoes/prevention/about-permethrin-treated-clothing-and-gear.html
  4. AVMA, External Parasites. https://www.avma.org/resources-tools/pet-owners/petcare/external-parasites
  5. National Pesticide Information Center, Permethrin Technical Fact Sheet (archived), reviewed March 2009. https://npic.orst.edu/factsheets/archive/Permtech.html
  6. US EPA stamped label, K9 Advantix II Medium Dog, EPA Reg. No. 11556-142, February 14, 2022 (PDF). https://www3.epa.gov/pesticides/chem_search/ppls/011556-00142-20220214.pdf
  7. US EPA, Read the Label First: Protect Your Pets. https://www.epa.gov/pets/read-label-first-protect-your-pets
  8. Sutton, Bates and Campbell, Clinical effects and outcome of feline permethrin spot-on poisonings reported to the Veterinary Poisons Information Service (VPIS), London, Journal of Feline Medicine and Surgery, 2007. https://pmc.ncbi.nlm.nih.gov/articles/PMC10822630/
  9. US EPA, Reregistration Eligibility Decision (RED) for Permethrin, EPA 738-R-06-017, April 2006 (PDF). https://www3.epa.gov/pesticides/chem_search/reg_actions/reregistration/red_PC-109701_1-Apr-06.pdf
  10. US EPA, EPA Evaluation of Pet Spot-on Products: Analysis and Plans for Reducing Harmful Effects. https://www.epa.gov/pets/epa-evaluation-pet-spot-products-analysis-and-plans-reducing-harmful-effects
  11. National Pesticide Information Center, Using Pesticides on Pets, last updated September 13, 2024. https://npic.orst.edu/health/pets2.html
  12. US FDA, Safe Use of Flea and Tick Products in Pets, content current as of 06/22/2021. https://www.fda.gov/consumers/consumer-updates/safe-use-flea-and-tick-products-pets
  13. US EPA, Controlling Fleas and Ticks on Your Pet. https://www.epa.gov/pets/controlling-fleas-and-ticks-your-pet
  14. International Cat Care, Permethrin Poisoning, updated 26th Sep 2025. https://icatcare.org/articles/permethrin-poisoning
  15. US EPA stamped label, Traveler's Supply Inc. Permethrin Clothing and Gear Insect Repellent, EPA Reg. No. 81402-1, stamped 08/27/2021 (PDF). https://www3.epa.gov/pesticides/chem_search/ppls/081402-00001-20210827.pdf
  16. ASPCA, Animal Poison Control. https://www.aspca.org/pet-care/animal-poison-control
  17. Pet Poison Helpline, About page. https://www.petpoisonhelpline.com/about/

Last reviewed 2026-09-21 · every claim on this page is sourced above